1. Technical Field
The present invention relates to the field of modem to modem data communication; and, more specifically, it relates to a modem to modem communication and three-way calling and call waiting telephony services.
2. Description of Related Art
A conventional communication system typically establishes an Internet data session through a local and a remote ISP (Internet Service Provider) modem via a telephone switching network. Similarly, other modem to modem communication uses the telephone switching network as the communication link. Such modems often share a single telephone line with other local telephony devices, e.g., telephones, facsimile machines, answering machines, etc.
To handle multiple incoming calls, telephone switching networks offer three-way calling and call waiting services. Such services can be accessed through manual interaction of a person using a telephone. Telephone switching networks have also added caller identification (caller ID) services to support call waiting. Thus, the person using the telephone may view the caller ID before deciding to accept an incoming call during a ongoing telephone conversation.
To maintain a data session between modems, continuous modem connection must be maintained during the data session. If after a period of time the modem signaling is lost, modems will conclude that the data session has been terminated and will disconnect.
When a telephone call waiting tone (indicating the presence of caller ID) is detected during a local modem to remote modem data session, a decoding process involving both the local modem and a telephone switching network CO (Central Office) may be undertaken to retrieve the caller ID. During the caller ID decoding process, however, the remote modem usually disconnects. Thus, the remote modem must be redialed to reestablish and continue the data session.
If the local modem does not attempt to decode the caller ID, the call waiting signaling will, at a minimum, interfere with ongoing communication and may cause the modems to hang up or retrain. Thus, the telephone switching network provides a mechanism for turning on and off the call waiting service. Before beginning the modem to modem data session, the call waiting service is turned off for the duration of the session. However, doing so prevents a user from receiving any other incoming calls on a shared telephone line. As a result, users are forced to add dedicated telephone lines for each type of telephony device in their premises.
Further disadvantages of the related art will become apparent to one skilled in the art through comparison of the related art with the drawings and the remainder of the specification.